ARMY TM 9-6115-666-13&P
AIR FORCE TO 35C2-3-505-1
184.108.40.206. Operating Generator Sets in Parallel. The generator sets can be operated in parallel through the
switch box or at the generator set load terminals. When paralleling at the generator set load terminals, refer to
paralleling procedures in TM 9-6115-645-10. When paralleling at the switch box, perform the following
Prior to making any connections for parallel operation, ensure that there is no input to the
load and that the generator sets are shut down. Failure to observe this warning can result in
serious injury or death by electrocution.
Never attempt to start the generator set if it is not properly grounded. Failure to observe
this warning can result in serious injury or death by electrocution.
a. Ensure that load requirement is equal to or below the combined rated capacity of the two generator
b. Perform the Preventive Maintenance Checks and Services (PMCS) listed as "BEFORE" in table 2-2.
Do not close the AC CIRCUIT INTERRUPTER switch on either of the generator sets or
close the load contactor at load until specifically directed to do so. Closing any of these
devices at any other time may severely damage one or both of the generator sets.
c. Refer to paragraph 220.127.116.11 steps b through i , to start the first generator set and bring it on line.
d. On the operating generator set (generator set 1) position UNIT-PARALLEL switch (10, figure 2-8) to
f. At switch box, set generator set switch S1 or S2 (7 or 8), to ON (up) (CHECK TO SEE THAT BOTH
INDICATOR LIGHTS, DS1 (5) AND DS2 (6) ARE ON).
g. At generator set control panel:
(1) Set UNIT-PARALLEL switch (10) to PARALLEL.
If SYNCHRONIZING LIGHTS (11) on generator set do not go bright and dark in unison, the
properly. Failure to observe this caution can result in damage to generator sets.